Eager sky watchers awaiting the longest annular solar eclipse of this millennium on Friday are likely to be greeted by partly cloudy sky and isolated rains.

An India Meteorological Department (IMD) outlook said that these less than promising “eclipse watch” conditions would prevail along an arc extending right from the country's northeast to southwest.

The partial cloud cover may in this manner hang over Arunachal Pradesh, West Bengal, Sikkim, Orissa, Andhra Pradesh, Karnataka, Tamil Nadu, Kerala, Lakshadweep and the Andaman and Nicobar Islands.

Cloud Cover

The Satish Dhawan Space Centre (SDSC) at Sriharikota and the Thumba Equatorial Rocket Launching Station (Terls) at the Vikram Sarabhai Space Centre where elaborate arrangements have been made to track the celestial spectacle are expected to variously fall under the cloud cover on the appointed day.

With one day to go, satellite pictures on Wednesday showed the presence of a bank of massive clouding off Indonesia and adjoining east Indian Ocean and southeast Bay of Bengal looking threateningly at Sri Lanka and southern Indian peninsula.

Meanwhile, minimum temperatures over the Indo-Gangetic plains were below normal by 2 to 5 deg Celsius over parts of west Rajasthan and the Indo-Gangetic plains. Maximum temperatures were appreciably below normal over most parts of Punjab, Haryana, Delhi, Uttar Pradesh, Bihar, sub-Himalayan West Bengal, Assam, Meghalaya and isolated pockets of west Rajasthan.

Cold day conditions continued to prevail over most parts of Punjab, Haryana, Delhi, Uttar Pradesh and Bihar and extended eastwards over sub-Himalayan West Bengal, Assam and Meghalaya.

Rains Over North-west

Isolated to scattered rainfall has occurred over most parts of northwest and central India and snowfall over western Himalayan region.

This is even as a trough in mid-tropospheric westerlies is expected to affect the western Himalaya region during the next 24 hours.

The trough represents a low-pressure area with ascending motion of air, which on cooling falls down as either or snow, depending on the respective altitudes.

The IMD has forecast scattered rainfall to continue over parts of plains of northwest and adjoining central India until Wednesday evening. Isolated to scattered rainfall activity over east India during the next two days.

Forecast up to Saturday spoke about the possibility of fog to very dense fog conditions in the morning hours over the plains of northwest India during next 24 hours and over entire Indo-Gangetic plains thereafter.

A slight rise has been indicated in maximum temperatures over the Indo-Gangetic plains from Thursday onwards. But cold day conditions may continue to occur over some parts of the plains during the next two days.

The minimum temperatures are expected to fall over northwest and central India during next three days as the westerly system moves east yielding space for cold northerly to northwesterlies.

Meanwhile, an easterly wave has been affecting south peninsular India over the past two days. This has also triggered confluence of opposing winds over central and east India, which would continue for the next two days as well.

According to the Chennai Regional Met Centre, rainfall has been reported from a few places over interior Karnataka over the past 24 hours.

Isolated rainfall occurred over coastal Andhra Pradesh, Telangana, Kerala, Lakshadweep, Tamil Nadu and coastal Karnataka as the rains propagated north-northeast into the interior. Bellary recorded a heavy rainfall of seven cm during this period.

Forecast until Friday spoke about the possibility of further rains at a few places over Andhra Pradesh. Isolated rain has been forecast over Tamil Nadu, Puducherry, Kerala, Lakshadweep, south interior Karnataka, coastal and north interior Karnataka.

An outlook by the US National Centres for Environmental Prediction continued to predict that the scattered rainfall over the peninsula would continue until January 20.